I just tested HVX200 and EE-S screen with Canon`s 58mm 250D and 500D achromats.
Both of those achtomats were small, it means with 58mm threads.
First off 500D doesn`t let you focus as close as 250D.
With 250D macro HVX was able to fill the full 35mm frame but image had little bit soft corners. See a frame grab here. I was holding that printed office paper sheet by hand in front of the lens so maybe some of the softness is because of that, centre to bottom right corner is quite sharp.

One more grab here. Still little bit soft.
I really don`t know how those $400 achromats can stand such tests? As far as I know even the Redrock`s achromat is soft from the corners when used wide open.

One other thing to mention that with 19mm ultrawide it has some vignetting but I haven`t seen any adapter footage that hasn`t it with full 19mm coverage.

One update on the focussing on the ground glass issue with the Sony FX1. With a 3 dioptries achromat I can get a full frame image of the GG at 30cm closest distance. This is fully zoomed in (focal length of 54mm).
The hotspot is gone ... but unfortunately this distance is completely impractical for building a short setup, which was my intention. Even if I fold the path of light with mirrors twice to rotate the image, it still is too long.

Yeah, there is drawn out that microlens arrays act as any other GG. You can experience such thing with optosigma and nikon screens as well but just pattern is random kind as there is random grinding done.

Low light bokeh in metro station, back lighted subject with direct sunlight to lens and low sun shining into the lens from the side. All taken with camcorder too close to the focusing screen and 28mm f2 lens without lens hood. Added compression to all that and this is how worse it became. Not too bad.

When camcorder lens was at widest angle fully open and gain at max setting the footage became softer as as seen in the metro station part.

One aspect that needs fruther study is that vibrating EE-S matte side facing the SLR lens isn`t that soft at the same settings.

It has been confirmed by Ben Winter that a $25 Nikon D100 replacement screen is as good if not better than Beattie when used in vibrating design.

It should be noted that through my experiences, these focusing screens have absolutely horrendous bokeh, and anyone desiring anything resembling a normal-looking image should avoid the D100 and Beattie.